Modelling and optimization for an operating giant gas plant in Egypt

An Egyptian gas-producing plant located in the north of Egypt on the coast of the Mediterranean Sea near Port Said city is designed mainly to receive and treat natural gas produced from offshore wells. The plant designed capacity is around 2800 million standard cubic feet per day (MMSCFD), which gives it a highly appreciated strategic importance. The primary plant process is removing H2S associated with the produced gas using amine solutions. The plant contains seven units called gas trains, which use packed columns for the removal. An additional acid gas removal unit was involved in the early production facility, which uses trays column. This study presented a comprehensive comparison study for the columns, packed versus trays, at different operating conditions, including gas flow rate, gas temperature, lean amine concentration, lean amine flow rate, and lean amine temperature. Two models simulating these systems were built using ASPEN HYSYS V12.1 simulation software. The reliability of the two models was verified by comparing the results with plant actual data. The results showed similar behavior trends with changes in operating conditions to optimize the production capacity. For the early production facility unit, the gas to contactor temperatures has been optimized at 29.5 °C, lean amine temperature at 52 °C with 44.5% concentration. The lean amine temperature for the gas train unit has been optimized at 41.5 °C with a concentration of 36%. Both units were compared under the same operating conditions to determine the economically practical unit.